Abstract: A transmission system of the kind comprising, on emission, a code converter for coding said signals into variable length words according to their occurrence probabilities, the word rate being determined by an emission clock, a synchronizing word generator operating at a frequency bound to said emission frequency, means for multiplexing words from the code converter and synchronizing-words, and an elastic memory connected to said multiplexing means, and, on reception, an elastic memory connected to said emission elastic memory, reading on emission and writing on reception being carried out at a rate determined by a transmission clock, means for detecting synchronizing-words at the output of said reception-memory and a decoder for deriving said signals from said variable length words, said system further comprising, on emission, means for supplying to said multiplexing means the drift of said emission frequency with respect to a frequency bound to said transmission frequency, and, on reception, a controlled osc